Dielectric thin films can be deposited for the purpose of fabricating electronic components by a variety of methods. One of these methods is physical vapor deposition (PVD) from a target of the desired material, otherwise known as sputtering. The sputtering method is known to people skilled in the art of thin-film deposition for the deposition of the conductive or semiconducting films (metals or conductive barriers). The method could be utilized also for the deposition of dielectrics. The sputtering process is utilizing cathode plasma discharge in vacuum resulting in the material transfer from the target to a substrate. The deposition can be done in an inert plasma sustaining gas ambient or in a reactive gas ambient, such as an inert/reactive gas mixture. Argon is frequently used as the inert plasma sustaining gas. Oxygen is a frequently used reactive gas for the deposition of oxide films. Other reactive gases such as nitrogen, nitrous oxide, etc. can be used as well. The quality of the thin dielectric film is heavily dependent on the quality and structure of the target material. Any impurities or trapped gases in the target are incorporated into the thin film, usually causing degradation of the film performance. The rate at which material is ejected from the target is also influenced by the target composition and density. A denser target can withstand higher power and have a resulting higher deposition rate and productivity of the fabrication process. Thus, the target quality and density will determine the film quality and productivity of the process. One of the challenges in fabrication of the target with a doped composition is the fact that the minor constituents (dopants) are added in substantially lower amounts (˜0.5-10% of the major constituents). If the dopants are not evenly distributed, they create local areas with different dielectric strength and density. If the dopants have multiple valent states, the uneven distribution of dopants will lead to generation of large pores, craters, or even blisters. Even distribution of the minor constituents in the composition is a key to the dielectric strength of the target, particulate control, and deposition rate of the sputtering process. Attempting to improve the distribution of the minor constituents by longer mechanical mixing/milling step results in micro-contamination of the target material with trace elements worn off the contacting parts.
In FIG. 1A, a sputtering target 100 is shown for a doped Barium-Strontium-Titanate (BST) formulation that was fabricated using a hot-press method with standard powders. The powders were prepared from calcined barium titanate powder and other standard pre-cursors using a conventional two-step method of mixing+calcination then re-mixing with dopant powders. This target using standard oxide powders is non-usable because of the heavy blistering of the material. If the hot-press process for forming the sputtering target is optimized or otherwise improved to reduce or eliminate the blistering then the grain size distribution 150 becomes too high, density of the sputtering target becomes low (e.g., <96% of the theoretical density) and the sputtering target material is porous as shown in FIG. 1B.